When creating a KVM guest you must always use the --accelerate option. If you do not, it will fall back to QEMU emulation.

the --cdrom option can point to an actual drive (ie, /dev/hdc), or a iso file on your local machine, or even a remote file (ftp, http, etc.).

ram is specified in MB, disk size is specified in GB.

the --disk option may be of more use to you the --file.

virt-manager

One of the features of virt-manager is the ability to create new guests by using a nice GUI. There are some features you will not have access to with this approach, but the majority of features you need will be there.

virt-clone

This is another command line program that will take an existing guest image and create a copy of it. Assignment of new UUIDs and network MACs is easily handeled here.